Pulmonary hypertension (PH), which includes pulmonary arterial hypertension (PAH), is a disease that can result in death and is characterized by increased pulmonary artery pressure and pulmonary vascular resistance. Some drugs that can be used to treat PH or PAH cannot be effectively administered orally for various reasons and are generally administered via subcutaneous, intravenous or intramuscular routes. These routes of administration generally require intervention by a healthcare professional, and can entail considerable discomfort as well as potential local trauma to the patient.
One example of such a drug is treprostinil. Treprostinil as the free acid has an absolute oral bioavailability of less than 10% and a very short systemic half-life due to significant metabolism. Treprostinil can be administered in an inhaled form, but about 50% of PAH patients cannot take inhaled treprostinil due to irritation. Treprostinil (also called Compound A herein) has the following structure:
Treprostinil can exist as a salt, such as a sodium or diethanolamine salt.